Towards a strategy for the introduction of information and computer literacy (ICL) courses

An important goal of the national policy on computers in education in the Netherlands is the familiarization of all citizens with information technology. This policy was a plea for some basic education in information and computer literacy. In the beginning of the implementation of this basic education for all a national survey (about grassroots developments) in Dutch junior secondary education was executed (Spring, 1984) with the following objectives: (i) to collect information which can serve as a baseline for the evaluation of future developments and (ii) to perform a context analysis to provide policy makers, innovation planners and curriculum developers with information about the state-of-the-art on information and computer literacy in the schools. The survey instruments were partly developed with as underlying structure some of the factors which are influencing the implementation of educational changes. The instruments were submitted to a sample of 462 schools representing the different types of junior secondary schools. Variation between the schools was obtained by distinguishing different levels of involvements of schools in information and computer literacy. This paper analyses how far in the schools, which are experimenting with information and computer literacy on their own initiative, some of the implementation factors of Fullan are fulfilled. Based upon this analysis a recommendation for a policy strategy for introducing this new domain in the schools is formulated

The implementation of the vegter yield criterion and a physically based hardening rule in finite elements

A new material description for sheet metal forming using Finite Elements has been developed. The description consists of a yield criterion and a hardening rule. In contrast to most former criteria the new criterion is based on multi-axial stress states. The yield criterion is extended with a physically based hardening rule, in which the flow stress depends on the strain and strain rate. A Limiting Dome Height test is used to examine the material description

Closing the Gap between the Workshop and Numerical Simulations in Sheet Metal Forming

The accuracy and reliability of numerical simulations of sheet metal forming processes do not yet satisfy the industrial requirements. In this paper we pay attention to the strategies which can be followed to decrease the gap between the real deepdrawing process and the predictions obtained from the simulation. We will focus on three aspects to improve the numerical simulations. The contact search for an accurate contact and friction behaviour is treated firstly. The friction behaviour itself is the second point of attention. Thirdly, attention is paid to drawbead modelling in 3D simulation

Equivalent drawbead model in finite element simulations

In 3D simulations of the deep drawing process the drawbead geometries are seldom included. Therefore equivalent drawbeads are used. In order to investigate the drawbead behaviour a 2D plane strain finite element model was used. For verification of this model experiments were performed. The analyses showed that not only the restraining force should be applied but also the strain changes. The effects of the restraining force and the strain change were implemented in an equivalent drawbead. The effect of using the equivalent drawbead is demonstrated with a few example

Optimising towards robust metal forming processes

Product improvement and cost saving have always been important goals in the metal forming\ud industry. Numerical optimisation can help to achieve these goals, but optimisation with a deterministic\ud approach will often lead to critical process settings, such that the slightest variation in e.g. material behaviour\ud will result in violation of constraints. To avoid a high scrap ratio, process robustness must be considered in the\ud optimisation model. Optimising for robustness includes Robust Manufacturing (RM) techniques, Optimisation\ud Under Uncertainty (OUU) methods and Finite Element (FEM) simulations of the processes. In this paper,\ud we review RM and OUU. Subsequently, the combination of Statistical Process Control (SPC), robust and\ud reliability based optimisation methods, and FEM-based process simulation implemented in AutoForm-Sigma\ud is presented. An automotive deep drawing application demonstrates the potential of strategies that optimise\ud towards robust metal forming processes

Modelling drawbeads with finite elements and verification

Drawbeads are commonly used in deep drawing processes to control the flow of the blank during the forming operation. In finite element simulations of deep drawing the drawbead geometries are seldom included because of the small radii; because of these small radii a very large number of elements is required in 3-D simulations. To cope with this problem, a 2-D analysis of the drawbead has been performed and the calculated restraining force will be applied in the near future in 3-D simulations with an equivalent drawbead element. Modelling drawbeads by only applying an additional restraining force is not satisfactory. During the flow of the material through a drawbead, the strain distribution changes and the material usually becomes thinner. These effects must be incorporated in the equivalent drawbead element.\ud \ud For the modelling of the drawbead a 2-D plane strain finite element model was developed. Several simulations were carried out to investigate the behaviour of the drawbead. Various geometries were investigated, the friction coefficient was varied and also the frictionless case was taken into account.\ud \ud To verify the model an experimental set-up was built. An extensive set of drawbead geometries was used. The results are compared with the finite element calculations and the similarity is very satisfactory

Recent developments in finite element simulations of the deep drawing process

Some new developments in a finite element code for the deep drawing process are presented\ud in this paper. First the phenomenon of friction is treated. A Stribeck friction model has been\ud developed which accounts for the dependency of the friction coefficient on the local contact\ud conditions. Secondly a new yield criterion has been developed by Vegter. This Vegter yield\ud criterion is based on multi-axial stress states. Finally attention will be paid to reduce the CPUtime\ud of a simulation when drawbeads are used. An equivalent drawbead model has been\ud developed to avoid an enormous increase in calculation time